Appl. Phys. Lett. 48(24), 16 Jun. 1986, p-1675-1677 proposes a monolithic semiconductor laser device comprising a semiconductor device layer integrally formed with a cavity facet and a reflection surface of an emitted laser beam with a gallium arsenide-based semiconductor material in general.
In the conventional semiconductor laser device disclosed in Appl. Phys. Lett. 48(24), 16 Jun. 1986, p-1675-1677, a cavity facet on a light-emitting surface side and a reflection surface extending in a direction inclined at 45° with respect to the cavity facet at a position spaced from this cavity facet by a prescribed distance are formed on a semiconductor device layer uniformly stacked on a substrate by ion beam etching. Thus, a laser beam emitted from the cavity facet can emit outside by being reflected in a direction perpendicular to the substrate by the reflection surface.
However, the monolithic semiconductor laser device proposed in Appl. Phys. Lett. 48(24), 16 Jun. 1986, p-1675-1677 requires a step of forming the reflection surface inclined at 45° with respect to the cavity facet by ion beam etching after forming the flat semiconductor device layer on the substrate in a manufacturing process, and hence there is such a problem that the manufacturing process is complicated. The reflection surface formed by ion beam etching is formed with small unevenness, and hence the laser beam emitted from the cavity facet is conceivably partly scattered on the reflection surface. In this case, there is also such a problem that luminous efficiency as the semiconductor laser device is reduced.